价值观传递给另一个视图控制器

问题描述：

我使用的核心数据有一个比较复杂的应用程序时，从管理对象消失，即除了在数据似乎消失了一个实例运作良好。我有一个托管对象类，pitLayer，有10个属性（字符串和数字），一个视图控制器（viewLayers），显示属于父对象的所有pitLayer对象，和一个视图控制器（editLayer）可以编辑（和创建）新的坑层对象。价值观传递给另一个视图控制器

当我创建一个新的pitLayer，然后返回到表视图，所有的属性表中正确显示。如果我立即回到editLayer，所有的值都显示正确。

如果我然后用editLayer编辑另一个pitLayer，除了2，硬度和botttomHardness（两个字符串）之外，我都可以得到正确的值，我仍然可以从前一个编辑好的pitLayer中获取值。

如果我加载editLayer首次与现有pitLayer硬度和bottomHardness返回零，所有其他值返回先前存储的值。

值越来越保存得当，它们可以在viewLayers中获取并返回正确的值，但是当他们在editLayer被取他们不返回正确的值。它只有2个属性，其他8个似乎工作得很好。

任何有关调试的建议？

这里是他们得到设置：

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{ if(component == kGrainTypeComponent){ layer.grainType = [[grainTypeValues objectAtIndex:row] valueForKey:@"code"]; }else if(component == kSecondGrainTypeComponent){ layer.secondGrainType = [[grainTypeValues objectAtIndex:row] valueForKey:@"code"]; } else if(component == kHardnessComponent){ layer.hardness = [[hardnessValues objectAtIndex:row] valueForKey:@"code"]; } else if(component == kSecondHardnessComponent){ layer.bottomHardness = [[hardnessValues objectAtIndex:row] valueForKey:@"code"]; } [self checkSavable]; }

而这里就是他们未能让后来检索：

-(void)resetDefaults{ 
if(edit == YES && layer != nil){//Edit an existing layer 
    if(layer.comments) 
     comments.text = layer.comments; 
    else 
     comments.text = @""; 
    if(layer.thickness){ 
     thicknessSlider.value = [layer.thickness floatValue]; 
     [self thicknessChanged]; 
    } 
    if(layer.grainSize){ 
     grainSizeSlider.value = [layer.grainSize floatValue]; 
     [self grainSizeChanged]; 
    }else{ 
     grainSizeSlider.value = 0; 
     grainSizeLabel.text = @""; 
    } 
    if(layer.density){ 
     densitySlider.value = [layer.density floatValue]; 
     [self densityChanged]; 
    }else{ 
     densitySlider.value = 0; 
     densityLabel.text = @""; 
    } 
    NSString *type = layer.grainType; 
    NSString *secondType = layer.secondGrainType; 
    NSString *hardness = nil; 
    hardness = layer.hardness; 
    NSString *bottomHardness = nil; 
    bottomHardness = layer.bottomHardness; 
    NSString *lwc = layer.liquidWaterContent; 
    NSUInteger typeIndex = 0; 
    NSUInteger secondTypeIndex = 0; 
    NSUInteger hardnessIndex = 0; 
    NSUInteger bottomHardnessIndex = 0; 
    NSLog(@"type:%@, hardness: %@, bottom hardness: %@", type, hardness, bottomHardness); 
    if(type){ 
     for(int i = 0; i < [grainTypeValues count]; i++){ 
      if([[[grainTypeValues objectAtIndex:i] valueForKey:@"code"] isEqualToString: type]){ 
       typeIndex = i; 
       break; 
      } 
     } 
    } 
    [picker selectRow:typeIndex inComponent:kGrainTypeComponent animated:NO]; 
    if(secondType){ 
     for(int i = 0; i < [grainTypeValues count]; i++){ 
      if([[[grainTypeValues objectAtIndex:i] valueForKey:@"code"] isEqualToString:secondType]){ 
       secondTypeIndex = i; 
       break; 
      } 
     } 
    } 
    [picker selectRow:secondTypeIndex inComponent:kSecondGrainTypeComponent animated:NO]; 
    if(hardness){ 
     for(int i = 0; i < [hardnessValues count]; i++){ 
      if([[[hardnessValues objectAtIndex:i] valueForKey:@"code"] isEqualToString:hardness]){ 
       hardnessIndex = i; 
       break; 
      } 
     } 
    } 
    [picker selectRow:hardnessIndex inComponent:kHardnessComponent animated:NO]; 
    if(bottomHardness){ 
     for(int i = 0; i < [hardnessValues count]; i++){ 
      if([[[hardnessValues objectAtIndex:i] valueForKey:@"code"] isEqualToString:bottomHardness]){ 
       bottomHardnessIndex = i; 
       break; 
      } 
     } 
    } 
    if(secondHardness) 
     [picker selectRow:bottomHardnessIndex inComponent:kSecondHardnessComponent animated:NO]; 
    if(lwc){ 
     for(int i = 0; i < [lwcValues count]; i++){ 
      if([[[lwcValues objectAtIndex:i] valueForKey:@"code"] isEqualToString:lwc]){ 
       lwcSlider.value = [[[lwcValues objectAtIndex:i] valueForKey:@"value"] floatValue]; 
       lwcLabel.text = [[lwcValues objectAtIndex:i] valueForKey:@"name"]; 
       break; 
      } 
     } 
    }else{ 
     lwcSlider.value = 0; 
     lwcLabel.text = @""; 
    } 
    if(layer.formationDate){ 
     datePicker.date = layer.formationDate; 
     [self dateChanged]; 
    }else{ 
     formationDate.text = @""; 
     datePicker.date = [NSDate date]; 
    } 

}else{//create a new layer 
    comments.text = @""; 
    thicknessSlider.value = 0; 
    thicknessLabel.text = @"0.0"; 
    grainSizeSlider.value = 0; 
    grainSizeLabel.text = @""; 
    densityLabel.text = @""; 
    densitySlider.value = 0; 
    lwcLabel.text = @""; 
    lwcSlider.value = 0; 
    formationDate.text = @""; 
    datePicker.date = [NSDate date]; 
    [picker selectRow:0 inComponent:kGrainTypeComponent animated:NO]; 
    [picker selectRow:0 inComponent:kSecondGrainTypeComponent animated:NO];  
    [picker selectRow:0 inComponent:kHardnessComponent animated:NO]; 
    if(secondHardness) 
     [picker selectRow:0 inComponent:kSecondHardnessComponent animated:NO]; 
} 
thicknessUnitLabel.text = layer.parentPit.depthUnit; 
locationUnitLabel.text = layer.parentPit.depthUnit; 
densityUnitLabel.text = layer.parentPit.densityUnit; 
if([layer.parentPit.densityUnit isEqualToString:@"kg/m3"]){ 
    densitySlider.maximumValue = 1000; 
    densitySliderDecimalCutoff = 0; 
}else{ 
    densitySlider.maximumValue = 100; 
    densitySliderDecimalCutoff = 20; 
} 
topLabel.text = [NSString stringWithFormat:@"%1.1F", [[layer topLocation] floatValue]]; 
bottomLabel.text = [NSString stringWithFormat:@"%1.1F", [[layer bottomLocation] floatValue]];

}

添加editLayer的代码 - 听起来好像有什么地方出错:) – deanWombourne

答

的值获得存储正确的，他们可以在 viewlayer中取回并返回co正确的值...

这表明值正在进入托管对象并保存到持久存储区。

...但是，当它们在editLayer中被提取时，它们不会返回正确的值。

对此的唯一解释就是您将UI元素连接到错误的管理对象，错误的属性或无对象。

调试，将需要看到的代码。

价值观传递给另一个视图控制器

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